The sound denoising algorithm is based on the popular spectral subtraction technique. Based on the spectrum of the vuvuzela sound, this denoising technique simply computes an antenuation map in the time-frequency domain. Then, the audio signal is restored by computing the inverse STFT. See [1-3] for more detail about the algorithm.
The zip file contains:
- the vuvuzela_denoising.m file
- the vuvuzela.wav audio file
To hear the result of this algorithm, go directly to: http://soundcloud.com/choc29/vuvuzela-correction-with-matlab
Note that better denoising audio results could be obtained by properly tuning the algorithm parameters.
 Steven F. Boll, "Suppression of Acoustic Noise in Speech Using Spectral Subtraction", IEEE Transactions on Signal Processing, 27(2),pp 113-120, 1979
 Y. Ephraim and D. Malah, “Speech enhancement using a minimum mean square error short-time spectral amplitude estimator,” IEEE. Transactions in Acoust., Speech, Signal Process., vol. 32, no. 6, pp. 1109–1121, Dec. 1984.
 S. Mallat, "A Wavelet Tour of Signal Processing", Academic Press, 3rd edition, 2008.